Introduction: Nowadays, the aquaculture industry has prospered all over the world, including Iran. However, the use of unconventional water resourses should be considered as an effective solution for the sustainable aquaculture development in the purpose of animal protein production and job security due to the global freshwater shortage crisis (Karimidastenaei et al., 2022). In this regard, Yazd provines in Iran has unconventional ground water resources with relatively warm and brackish water that does not have access to inland water bodies and has provided a suitable environment for the cultivation and propagation of non-native species (Alizadeh and Bemani, A., 2012; Rajabipour et al., 2013).
Materials and Method: In this study, some physicochemical parameters, ions, and heavy metals of the well waters from four different farms in Bafq (Yazd) were measured. The water samples from 6 wells were transported to the laboratory within a maximum of 6 h under the cold-chain conditions and the physical (salinity, temperature, and electrical conductivity) and chemical (pH, total dissolved solids, total hardness, total alkalinity, ammonia, nitrate, nitrite, chlorine, sulfate, carbonate, bicarbonate, phosphate, sodium, calcium, magnesium, and potassium) parameters of the groundwater sources were analyzed according to international standard methods (APHA, 2012) and Iranian national standards 1053. Sodium and potassium ions were measured with a film photometer (Carning 410), and titrimetric tests were also performed to determine hardness, calcium, magnesium, and chlorine. Heavy metals (iron, zinc, chromium, copper, arsenic, aluminum, and boron) were measured after a digestion step with concentrated nitric acid using an atomic absorption spectrometer (SpectrAA-200, Varian, Mulgrave, Australia) (Baldwin and Marshall, 1999). It should be noted that the parameters of temperature, salinity, oxygen, electrical conductivity and pH were measured at the sampling site by a portable HACH device (HQ30d, HACH, USA). Some tests were performed by the National Research Center of Saline-waters Aquatics. All chemicals used in the tests were manufactured by Merck, Germany.
Results and Discussion: Water quality assessment is an essential step for any aquaculture operation. Aquatic organisms experience stress when ecological conditions are unfavorable. These levels of stress negatively affect feeding and growth rates, ultimately reducing production yields (Carbajal-Hernández et al., 2013). Various aquatic species have been introduced for aquaculture in desert/aride or inland waters in the world, including tilapia (Nile tilapi is the main species), North African catfish, some carp species, sea bass, sea bream, and some ornamental species (Sadek et al., 2011). The are seven popular aquaculture species in Iran that can be cultured in brackish water, including rainbow trout (Oncorhynchus mykiss), common carp (Cyprinus carpio), Nile tilapia (Oreochromis niloticus), Asian sea bass (Lates calcarifer), cobia (Rachycentron canadum), bluga (Huso huso), and whiteleg shrimp (Litopenaeus vannamei). According to the results, the total water hardness (2261-2802 g/l calcium carbonate) and the amounts of some of the main water ions such as calcium, magnesium, and sulfate were in the range of 448.1-472. 2, 568-500.7, and 3840.4-4200.2 mg/l, respectively. The level of potassium ion (37.3-41.4 mg/l) in the wells was recorded lower than the desired levels in brackish waters. However, the range of pH, total alkalinity, and heavy metals were in accordance with existing standards, and were suitable for aquaculture. Hardness refers to the amount of alkaline earth elements such as calcium and magnesium, as well as many other ions including aluminum, iron, manganese, strontium, and zinc in water (Verma et al., 2022). Excessive water hardness can have detrimental impacts on fish and shellfish, especially crustaceans, including reduced growth, disruption of ion homeostasis, altered energy metabolism, and even histopathological lesions (Boyd and Tucker, 2012; Swain et al., 2020; Limbaugh et al., 2021). Brackish groundwaters are generally poor in potassium ions, largely due to the fact that potassium is absorbed and unavailable by cation exchange in clay soils (Stumm and Morgan, 2013). The most common substance used to increase potassium concentration in fish pond water is potassium chloride (KCl) fertilizer, which contains 50% potassium (Boyd, 2003).
Conclusion: The results of water quality requirements for some commercial aquatic species showed that the physicochemical parameters of the studied wells are within the tolerable range of rainbow trout, common carp, cobia, and Nile tilapia. Also, the quality of these waters is quite favorable for the cultivation of Asian sea bass. However, in Pacific white shrimp farming practices, it is necessary to perform ionic water manipulations due to the low potassium content, low salinity, and high total hardness in the studied wells.
Conflict of Interest:The authors declare that there is no conflict of interest.
Acknowledgment:This article is prepared from a research project that has been approved and supported by Iranian Fisheries Science Research Institute (IFSRI).
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